8. (a) Design a half-subtractor circuit with inputs x and y and outputs Diff and Bout. The circuit subtracts the bits x - y and places the difference in D and the borrow in Bout. and Bout. The circuit subtracts x -y- Bin, where B in is the input borrow, Bout is the output borrow, and Diff is the difference 9. Design a combinational circuit with three inputs, x, y and z, and three outputs, A, B, and O. When the binary input is 0, 1, 2, or 3, the binary output is two greater than the input. When the binary input is 4, 5, 6, or 7, the binary output is three less than the input. 10. Design a four-bit combinational circuit 2's complementer. (The output generates the 2's complement of the input binary number.)